An automatic transmission is generally controlled by a selector and a shift actuator, whereby shift gates are preselected by the selector, within which gears are engaged or released by the shift actuator. For a fast and precise shifting, it is especially necessary to know the exact position of the shift actuator and/or of a shift element controlled by it. The position of the shift actuator and/or of a shift element operated by it is generally sensed by means of an incremental sensor, which e.g. counts a rotation converted into a linear motion in the form of angular increments and increases or decreases its counter status by 1 with each angular increment, depending on the direction of rotation. In order to make a decision about the absolute position from the counter status, the knowledge of a reference position is necessary, starting from which the absolute position can be determined when the change in the counter status is known.
For example, if the reference position and/or the counter status corresponding to the reference position is lost after a reset or as a result of a system error, referencing must be performed again, in that the shift element is moved, by means of the actuator, to one or more reference positions that are recognized and have the counter status stored for them. If at first no position information is available, during a sensing in shifting direction and/or movement of the shift element in the direction of engaging a gear, it may happen that sensing takes place opposing a synchronization of the respective gear. If this sensing leads to engagement of a gear that is not appropriate for the vehicle speed, e.g., engagement of first gear at a driving speed of 100 km/h, serious transmission damage can occur.